Enhancement of the biofilm formation on polymeric supports by surface conditioning

The aim of this study is to determine the influence of the surface properties on the microbial adhesion to different substratum. Six polymer supports have been selected. Further, the possibility to improve the biofilm growth on the carriers using a conditioning film of PMMA/PAC was proposed. The role of the hydrophobic/hydrophilic interactions between bacterial and support surfaces was determined using contact angle measurements. Scanning electron microscopy was used to compare biofilm morphology on different supports. Mid-infrared microspectroscopy has allowed analyzing in situ the attached biomolecules at various periods of the biofilm development. The infrared attenuated total reflectance method was found to be convenient for surface analysis. Epifluorescence microscopy after DAPI labeling was used to reveal the biofilm structure and the cell density. Indigenous microorganisms from an industrial wastewater-recycling unit were used. The monitoring of the biofilm formation showed the advantages of the coated materials, which allowed faster colonization and higher cell densities. Optimal colonization was observed when the difference between the surface free energies of the support and the bacteria was maximized. Tests on the biodegradation of wastewater exhibiting high COD concentrations attest the biofilm potential in fast COD decay.